Using DNA metabarcoding for assessing chironomid diversity and community change in mosquito controlled temporary wetlands

By

Theissinger, Kathrin
Kästel, Anna
Elbrecht, Vasco
Makkonen, Jenny
Michiels, Susanne
Schmidt, Susanne
Allgeier, Stefanie
Leese, Florian 1978-
Brühl, Carsten

Type

Article

Date of Publication

2018-1-15

Original Publication

Metabarcoding and metagenomics

Volume

2

Pages

1--13

Subjects

Bacillus thuringensis var. israelensis (Bti) , Barcode of Life Database (BOLD) , chironomid saprobic index , cytochrome oxidase subunit I (COI) , ecotoxicology , macrozoobenthos emergence , operational taxonomic units (OTU)

Contributed by

Pensoft Publishers

Language

English

Published by

Bulgaria Pensoft Publishers 2017-

Identifiers

DOI: https://doi.org/10.3897/mbmg.2.21060

 

Abstract

The biocide Bacillus thuringiensis var. israelensis (Bti) is widely applied for mosquito control in temporary wetlands of the German Upper Rhine Valley. Even though Bti is considered environmentally friendly, several studies have shown non-target effects on chironomids, a key food resource in wetland ecosystems. Chironomids have been proposed as important indicators for monitoring freshwater ecosystems, however, morphological determination is very challenging. In this study, we investigated the effectiveness of metabarcoding for chironomid diversity assessment and tested the retrieved chironomid operational taxonomic units (OTUs) for possible changes in relative abundance and species diversity in relation to mosquito control actions in four temporary wetlands. Three of these wetlands were, for the first year after 20 years of Bti treatment, partly left Bti-untreated in a split field design, and one wetland has never been treated with Bti. Our metabarcoding approach detected 54 chironomid OTUs across all study sites, of which almost 70% could be identified to species level comparisons against the BOLD database. We showed that metabarcoding increased chironomid species determination by 70%. However, we found only minor significant effects of Bti on the chironomid community composition, even though Bti reduced chironomid emergence by 65%. This could be due to a time lag of chironomid recolonization, since the study year was the first year of Bti intermittence after about 20 years of Bti application in the study area. Subsequent studies will have to address if and how the chironomid community composition will recover further in the now Bti-untreated temporary wetlands to assess effects of Bti.